Businesses and residents in Eastbourne are being asked to assess the impact of the largest free airshow in Sussex.

An Eastbourne Borough Council scrutiny task group is examining the value, environmental impact and overall benefits of Airbourne.

The four-day council-run airshow regularly attracts up to 800,000 people to Eastbourne seafront in the middle of August.

But critics have said the £20 million that the Tory-run council has claimed it is worth to the economy is an invention designed to create better headlines.

The Eastbourne Green Party has also raised concerns about the pollution caused by so many aircraft over the town. The party said the fact the main sponsor, Brighton-based CSMA, has pulled out of sponsoring this years event suggests it is not as lucrative as the council claims.

The greens have called for Airbourne to be scrapped and instead have public money invested into an alternative events programme, making use of other venues apart from the seafront.

Its spokesman Clive Gross said: Because pressure was put on the council last summer about the true value of Airbourne I feel it has taken this action to try to justify the event. Our suspicion is that they are hoping this will give them the answers they want but at least we have forced a debate on the subject.

To assess the overall impact of Airbourne, the group has put questions to the business community and residents in Eastbourne.

They include:

Do you think the airshow is a benefit to Eastbourne?

What do you consider to be the main environmental impact of the airshow on Eastbourne?

Are you or is your business affected by the increased number of visitors to Eastbourne?

The study will result in a meeting at the town hall on Thursday where invited parties will gather to comment on Airbourne issues. Full findings will be published in the summer. However, the greens criticised the council for holding the meeting behind closed doors.

Deputy borough council leader David Elkin has dismissed out of hand suggestions Airbourne could be scrapped and said other sponsors are being looked at.